EP0151811B1 - Method for maskless ion implantation - Google Patents

Method for maskless ion implantation Download PDF

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Publication number
EP0151811B1
EP0151811B1 EP84116489A EP84116489A EP0151811B1 EP 0151811 B1 EP0151811 B1 EP 0151811B1 EP 84116489 A EP84116489 A EP 84116489A EP 84116489 A EP84116489 A EP 84116489A EP 0151811 B1 EP0151811 B1 EP 0151811B1
Authority
EP
European Patent Office
Prior art keywords
substrate
ion
ion beam
scanning
clock frequency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP84116489A
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German (de)
English (en)
French (fr)
Other versions
EP0151811A3 (en
EP0151811A2 (en
Inventor
Shigeru Okamura
Takao Taguchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Publication of EP0151811A2 publication Critical patent/EP0151811A2/en
Publication of EP0151811A3 publication Critical patent/EP0151811A3/en
Application granted granted Critical
Publication of EP0151811B1 publication Critical patent/EP0151811B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26—Bombardment with radiation
    • H01L21/263—Bombardment with radiation with high-energy radiation
    • H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
    • H01J37/304—Controlling tubes by information coming from the objects or from the beam, e.g. correction signals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
    • H01J37/317—Electron-beam or ion-beam tubes for localised treatment of objects for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation
    • H01J37/3171—Electron-beam or ion-beam tubes for localised treatment of objects for changing properties of the objects or for applying thin layers thereon, e.g. for ion implantation for ion implantation
    • H01J37/3172—Maskless patterned ion implantation

Definitions

  • the present invention relates to ion implantation of selected impurities or dopants into a substrate of semiconductive material without utilizing a mask, and more particularly to form an ion implanted pattern by selectively scanning a focused ion beam on the surface of a processing substrate.
  • Ion implantation methods of the prior art have generally required the use of masks, and it is customary to use an ion beam to implant dopants through a mask placed either directly upon or spaced some distance from the target substrate. Ion implantation with the mask located directly on the substrate, though reducing the lateral migration associated with the diffusion, still is subject to the costs of the photolithographic process.
  • ion implantation through an apertured mask, spaced from the substrate eliminates the necessity of masking and etching step; new problems, however, occur in this approach.
  • certain configurations may not be obtained by use of masks spaced from the target substrate.
  • the prior art has recognized the need for a method of ion implantation which avoids these difficulties and thus, maskless ion implantation systems have been proposed.
  • a substrate may be uniformly implanted by applying a couple of wafers in a mechanically scanning apparatus, where they are exhibited to an ion beam.
  • the ion beam power is distributed over several wafers simultaneously and the wafers are moved in a fully mechanical X- and Y-motion to scan the whole batch of wafers through a stationary beam.
  • the wafers are allowed several coarse scans through the beam rather than a single fine scan.
  • Another processing method using a focused ion beam is known from EP 0 082 639, in which a focused ion beam is used to etch a desired pattern into a substrate.
  • the desired etching depth is preset as a function of location.
  • the etching time, the acceleration voltage and the ion dose may be varied according to different patterns to be etched into the substrate.
  • the table carrying the substrate is mechanically movable.
  • one object of the present invention is to provide an improved method for maskless ion implantation.
  • N being an integer greater than one
  • the values of N and the clock frequency being chosen such that a predetermined ion density is obtained.
  • One basic idea of the invention is to provide an ion implantation method providing a desired dose which can be controlled freely and continuously and which can be easily changed for providing different implantation dosages.
  • the invention provides a freely and continuously variable dosage without readjustment of the focusing system to ensure a sharp ion beam spot.
  • the dosage may only be varied in a coarse manner. Therefore incremental changes of the dosage or even continuously variable dosage cannot be made available according to above- mentioned.
  • the inventive idea of multiple scanning decreases the risk of causing thermal defects of the substrated which can be effected by either selecting too low clock frequency or too high beam current.
  • the beam current and the focus will be adjusted once, the remaining parameters clock frequency, scanning number and pitch will then be, according to the invention, available to continuously vary the dosage and to maintain uniform doping on the substrate.
  • clock frequency is not controllable continuously in methods according to the above described state of the art the dosage, according to such methods, may be controlled continuously only by adjusting the beam current, and thus misadjusting the focus.
  • inventive concept allows for varying the dosage continuously without the need of readjusting the focus.
  • a focused ion beam is measured to provide a beam current.
  • the data of the beam current is applied to a control unit.
  • the control unit receives a pattern data to be scanned and an implantation dosage data.
  • the control unit determines the outputs a data for clock frequency and a scanning number in order to provide a desired dosage.
  • the clock frequency is the one of clock for moving or shifting the focused ion beam step by step during the beam scanning.
  • V.F.O. variable frequency oscillator
  • the scanning conditions are precisely controlled in order to attain the desired implantation dosage.
  • Fig. 1A is a schematic plan view of the layout of a gallium arsenide (GaAs) field effect transistor (FET).
  • the FET has a gate electrode G, a source region S, a drain region d and channel region C.
  • a distance from a source S to a drain d is a channel length.
  • High performance devices typically having channel lengths of 3-6 microns (micrometers) have been proposed.
  • Fig. 2 illustrates a configuration of ion implantation system.
  • lons emitted from liquid metal ion (LMI) source 1 are controlled by an ion control electrode 2, beam alignments 4a, 4b and 4c, and a blanking electrode 6. They are filtered by ExB mass filter 7a which selects the ion and purity of the dopant by electric and magnetic cross field and mass separator slit 7b.
  • the doping ions are focused onto a target 12 with approximately unitary magnification.
  • the doping ions have been focused to spot diameters ranging from 0.1 to 3.0 micrometer at about 50 keV with a constant current density of 0.5 A/cm 2.
  • the lens 3, 5, and 8 also accelerate or decelerate the ion beam.
  • the final beam energy at the target 12 on the stage 11 can be varied from 40 to 200 keV.
  • the ion source 1 is movable to align the ion beam with the electro-optical axis of the lens.
  • the deflector 9 is used to electrostatically scan the ion beam across the target 12 and for calibrating astigmatism.
  • a 100 keV ion beam can be deflected over the entire scan field of 500 micrometer retaining a 0.1 micrometer diameter of focused beam.
  • a central processing unit (CPU) 21 controls an ion beam system of the apparatus.
  • the CPU 21 receives an input data which includes pattern data 22 and doping data 23 stored in magnetic tape, and data coming from probe 10 for ion current measuring. Then the CPU 21 generates control signals to the element of the apparatus to control the system, such as the lens system, a faraday cup 10, the stage 11, and a pattern generator 24.
  • the implantation dose D (ions/cm 2 ) is given by: where, Ip is ion current (A), K is charge state of ions, S is an area of implanted region, and q is an electric charge unit (1.602. 10 -19 coulomb). Therefore, the implantation dose D (ions/cm 2 ) is controlled by ion current Ip and ion implanting time T (dwell time).
  • the ion beam is scanned step by step (not continuously) as shown in Fig. 1B.
  • the implanted dose numbers D 1 is proportional with ion beam diameter and ion beam density, and inversely proportional to the clock frequency f c and squares of pitch (p 2 ).
  • the ion current Ip and the scanning number N must be controlled in order to obtain a desired dose D. But when ion current Ip is varied, the focus system must be adjusted in order to attain high resolution. So, it is very difficult to vary the ion current Ip.
  • the scanning of the ion beam is linked to the clock frequency and such clock frequency f c is fixed for prior art ion implantation apparatus. Therefore, the dose can only be varied discretely and in state of the art methods it is impossible to vary the dose D precisely.
  • Fig. 3 is a schematic block diagram illustrating an ion implantation apparatus according to the present invention.
  • the figure illustrates the basic elements of a focused ion beam system of the apparatus corresponding to that of Fig. 2.
  • the difference between the apparatus of Fig. 3 and Fig. 2 is that there is further provided a variable frequency oscillator (V.F.O.) 25.
  • V.F.O. variable frequency oscillator
  • Fig. 3 same or similar reference numerals denote the same or similar parts to Fig. 2.
  • the function of the focused ion beam system is to produce and deliver ions in the range of energies from 40 to 200 keV to a target substrate 12.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physical Vapour Deposition (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
EP84116489A 1983-12-29 1984-12-28 Method for maskless ion implantation Expired - Lifetime EP0151811B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP58251453A JPS60143630A (ja) 1983-12-29 1983-12-29 イオン注入方法
JP251453/83 1983-12-29

Publications (3)

Publication Number Publication Date
EP0151811A2 EP0151811A2 (en) 1985-08-21
EP0151811A3 EP0151811A3 (en) 1986-12-30
EP0151811B1 true EP0151811B1 (en) 1990-09-05

Family

ID=17223048

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84116489A Expired - Lifetime EP0151811B1 (en) 1983-12-29 1984-12-28 Method for maskless ion implantation

Country Status (5)

Country Link
US (1) US4641034A (ja)
EP (1) EP0151811B1 (ja)
JP (1) JPS60143630A (ja)
KR (1) KR890003497B1 (ja)
DE (1) DE3483157D1 (ja)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6180744A (ja) * 1984-09-27 1986-04-24 Hitachi Ltd イオンマイクロビ−ム装置
JP2537492B2 (ja) * 1986-06-05 1996-09-25 東京エレクトロン 株式会社 イオン注入装置
US4835399A (en) * 1986-08-22 1989-05-30 Hitachi, Ltd. Charged particle beam apparatus
US4736107A (en) * 1986-09-24 1988-04-05 Eaton Corporation Ion beam implanter scan control system
JPH01503580A (ja) * 1987-05-11 1989-11-30 マイクロビーム・インコーポレーテッド 最適化した集束イオンビーム装置を用いたマスク修復
US5035787A (en) * 1987-07-22 1991-07-30 Microbeam, Inc. Method for repairing semiconductor masks and reticles
US4967380A (en) * 1987-09-16 1990-10-30 Varian Associates, Inc. Dual channel signal processor using weighted integration of log-ratios and ion beam position sensor utilizing the signal processor
US4929839A (en) * 1988-10-11 1990-05-29 Microbeam Inc. Focused ion beam column
US4976843A (en) * 1990-02-02 1990-12-11 Micrion Corporation Particle beam shielding
US5401963A (en) * 1993-11-01 1995-03-28 Rosemount Analytical Inc. Micromachined mass spectrometer
US5449916A (en) * 1994-09-09 1995-09-12 Atomic Energy Of Canada Limited Electron radiation dose tailoring by variable beam pulse generation
EP1305452A4 (en) * 2000-07-14 2007-12-26 Tel Epion Inc METHOD AND DEVICE FOR GAS CLUSTER ION BEAM SIZING AND WORKPIECE PROCESSING
DE10057656C1 (de) * 2000-11-21 2002-04-04 Rossendorf Forschzent Verfahren zur Herstellung von integrierten Abtastnadeln
WO2002052608A2 (en) * 2000-12-26 2002-07-04 Epion Corporation Charging control and dosimetry system for gas cluster ion beam
DE60118070T2 (de) * 2001-09-04 2006-08-17 Advantest Corp. Partikelstrahlgerät
US7061591B2 (en) * 2003-05-30 2006-06-13 Asml Holding N.V. Maskless lithography systems and methods utilizing spatial light modulator arrays
US8278220B2 (en) * 2008-08-08 2012-10-02 Fei Company Method to direct pattern metals on a substrate
US20120213319A1 (en) * 2009-08-14 2012-08-23 The Regents Of The University Of California Fast Pulsed Neutron Generator

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4017403A (en) * 1974-07-31 1977-04-12 United Kingdom Atomic Energy Authority Ion beam separators
JPS56126918A (en) * 1980-03-11 1981-10-05 Hitachi Ltd Injecting device for ion
JPS5727026A (en) * 1980-07-25 1982-02-13 Hitachi Ltd Ion implantation
JPS57132660A (en) * 1981-02-09 1982-08-17 Fujitsu Ltd Method of ion implantation
US4433247A (en) * 1981-09-28 1984-02-21 Varian Associates, Inc. Beam sharing method and apparatus for ion implantation
JPS5894746A (ja) * 1981-11-30 1983-06-06 Nec Corp イオンビ−ム静電走査装置
JPS58106823A (ja) * 1981-12-18 1983-06-25 Toshiba Corp イオン注入方法
JPS58106750A (ja) * 1981-12-18 1983-06-25 Toshiba Corp フオ−カスイオンビ−ム加工方法
US4421988A (en) * 1982-02-18 1983-12-20 Varian Associates, Inc. Beam scanning method and apparatus for ion implantation
US4517465A (en) * 1983-03-29 1985-05-14 Veeco/Ai, Inc. Ion implantation control system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENTS ABSTRACTS OF JAPAN, vol. 6, no. 6 (E-89)[884], 14th January 1982; & JP-A-56 126 918 (HITACHI SEISAKUSHO K.K.) 05-10-1981, & US-A-4 494 005 *

Also Published As

Publication number Publication date
KR850005149A (ko) 1985-08-21
EP0151811A3 (en) 1986-12-30
EP0151811A2 (en) 1985-08-21
DE3483157D1 (de) 1990-10-11
KR890003497B1 (ko) 1989-09-22
JPH0213458B2 (ja) 1990-04-04
US4641034A (en) 1987-02-03
JPS60143630A (ja) 1985-07-29

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